Need help with this question. I'm not sure if it's C or D and need to know why.

Of (1) the unemployment rate, (2) the employmenttopopulation ratio, and (3) the labor force participation rate, which of the three is (are) unaected when, all else equal, certain unemployed persons in the labor force become discouraged workers? 0 Only the unemployment rate 0 Both the unemployment rate and the omploymont-laopopulation ratio Only the employmem-to-population ratio 0 Only the labor force participation rate